Insulin Types: Which Is Better for You?

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Insulin Types: Which Is Better for You?

Insulin has come a long way since a 14-year old boy with type 1 diabetes received the first injection of insulin in 1922. The first commercial insulins were bovine (cow) and porcine (pig) formulations that lowered blood sugar levels, but at a cost: these insulins were highly impure and caused allergic reactions ranging from itchy, lumpy skin to anaphylactic shock. Over time, contaminants were removed from beef and pork insulin, although they still caused lipoatrophy, which is a loss of fat tissue at the injection site.

Fast forward to 1978 when the first human insulin was created through biotechnology, called Humulin. In 1996, Eli Lilly debuted the first analog insulin lispro (brand name Humalog). Analog insulin is a genetically modified insulin, meaning that the amino acid sequence is altered to affect insulin absorption and action in the body.

Since then, a number of different types of insulin have hit the market, making it a little easier to manage blood sugar levels. But how do you choose the best insulin for you?

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First things first

If you have type 1 diabetes, you likely know that you need to take insulin, either by injection or by using an insulin pump. You might be less than thrilled about having to do this, and some of you might be feeling stronger emotions about having to inject insulin (which is perfectly normal, by the way). It might be helpful to have a basic understanding of insulin in terms of how it works and why you need it.

• Insulin is a hormone made in the beta cells of the pancreas, and it works to lower blood sugar (glucose) levels.

• Injected insulin replaces the insulin that the body naturally makes, similar to someone who takes thyroid hormone medication to replace what their thyroid would make if it were able.

• Insulin is safe and is often considered the best way to lower blood sugar.


• Insulin comes in different strengths. The most common “strength” in the U.S. is U-100 insulin (100 units per milliliter) but other strengths are available, too, such as U-200, U-300 and U-500. These are more concentrated forms of insulin.

• There are different types of insulin. Some work very fast, some work moderately fast, some are slower-acting and last for a longer period of time. If you have type 1 diabetes and are injecting insulin, you will likely need to take two different types of insulin: a fast-acting one and longer-acting one.

• There are several different insulin manufacturers in the U.S., and they all make similar types of insulin, with the exception of one company that makes an inhalable insulin.

• Insulin’s primary side effect is hypoglycemia, or low blood sugar. There are ways to prevent and treat hypoglycemia that you’ll need to learn about.


Insulin action

While all types of insulin work to lower blood sugar, they do differ from each other in the following ways:

• Onset: how long it takes insulin to start working after injection
• Peak: time after injection when insulin is working its hardest to lower blood sugar
• Duration: how long insulin continues to work after injection

If you’re new to type 1 diabetes, you might be wondering why your provider has prescribed two different types of insulin. Here’s a helpful way to understand it:

Background (basal) insulin

This insulin is either intermediate- or long-acting and helps to control glucose levels overnight and between meals. Background insulin is generally taken one to two times each day.

Mealtime (bolus) insulin

This is a very fast- or fast-acting insulin that is taken before meals to prevent blood sugar levels from climbing too high. Sometimes this insulin is taken to “correct” or lower blood sugar levels between meals, as well. The number of mealtime insulin injections you need is generally based on how many meals you eat each day.


Insulin types

Today there are seven main types of insulin available. These include the following:

Very fast-acting

Right now, there is one brand called Fiasp, which is a version of Novo Nordisk’s Novolog insulin. Fiasp is meant to be taken right before a meal, but because it works so quickly, it can be taken up to 20 minutes after the start of a meal. Its onset is several minutes after injection, its peak is 1.5 tp 2 hours, and its duration is five to seven hours.


Many people use fast-acting insulins, such as Humalog (lispro), Novolog (aspart) and Apidra (glulisine). They have an onset of less than 15 minutes, peak in 30–90 minutes, and a duration of three to five hours. Fast-acting insulins are given before meals.


Regular insulin (Humulin R and Novolin R) has been available for many years and is still used. It starts working 30 to 60 minutes after injection, so if you take this insulin, you need to take it at least 30 minutes before a meal. It peaks within two to four hours, and its duration is three to five hours, but it may last longer.


NPH (Humulin N and Novolin N) is a more middle-of-the-road insulin in terms of how quickly it starts to work. It starts to work within one to three hours, peaks at about eight hours, and generally lasts 12 to 16 hours. Most people who use NPH insulin need to take it twice daily.


Long-acting insulin

Lantus, Basaglar and Toujeo (glargine), Levemir (detemir) and Tresiba (degludec) are longer-acting in terms of when they start working. (Toujeo is an example of a concentrated insulin in that it has 300 units per milliliter). Their onset is generally one to three hours, they have a minimal peak and they can last up to 24 hours. Tresiba lasts more than 24 hours. These insulins are typically taken once daily, although some people take them twice a day.

Pre-mixed insulins

These insulins are a combination of background and mealtime insulin. Humulin 70/30 and Novolin 70/30 combine NPH with a short-acting (regular) insulin. Humalog 75/25 and Novolog 70/30 combine NPH with fast-acting insulin (lispro or aspart). Ryzodeg 70/30 combines degludec and aspart insulins. Using a combination insulin can limit the number of injections that you give yourself in a day, but the downside is that there isn’t a lot of flexibility with dosing if you, say, need more of the fast-acting insulin and less of the longer-acting insulin.

Inhaled insulin

The only inhaled insulin on the market is Afrezza. Afrezza is a fast-acting insulin that is taken before meals. People with type 1 diabetes still need to inject a longer-acting insulin if they use Afrezza. Afrezza is not suitable for people who smoke or who have a chronic lung disease.

What insulin should you take?

It can seem very confusing once you realize all of the insulin options that are available. Talk with your health-care provider and/or diabetes educator to determine the best types of insulins for you. You might decide, for example, that you want to use a pre-mixed insulin, such as Humalog 75/25 based on your schedule and eating habits. If you’re always on the go and are never quite sure when you’ll be eating your meals, the newer insulin, Fiasp could be a good choice for you, along with a long-acting insulin.

Another factor to consider is cost and whether or not your insulin is covered by your health insurance. Many health plans have “preferred” insulins (and other medications) on their formulary, so you may be somewhat limited with what you can use. Check with your health plan to find out what insulins they cover. Even with insurance coverage, however, the cost of insulin can be prohibitive, especially the newer insulins. The old “standbys,” Regular and NPH are usually much less expensive than, say, Novolog and Tresiba, and can be purchased in drugstores without a prescription. Walmart sells its own brand of Regular, NPH and Humulin 70/30 under the brand, ReliOn, and each vial of insulin typically costs $25.00.

If you have trouble affording your insulin, check the insulin manufacturer’s website for coupons, and look into the manufacturer’s patient assistance programs, as well. The American Diabetes Association offers help with how to afford insulin at the website, and another resource is the Affordable Insulin Project at

Finally, let your provider know if you have trouble affording your insulin, or if you would like to explore another type of insulin to try. He or she should be willing to work with you to come up with an insulin regimen that works with your lifestyle as well as your budget.

Want to learn more about insulin? Read “What Does Insulin Do?” and “Insulin Basics.”

Amy Campbell, MS, RD, LDN, CDCES

Amy Campbell, MS, RD, LDN, CDCES

Amy Campbell, MS, RD, LDN, CDCES on social media

A Registered Dietitian and Certified Diabetes Educator at Good Measures, LLC, where she is a CDE manager for a virtual diabetes program. Campbell is the author of Staying Healthy with Diabetes: Nutrition & Meal Planning, a co-author of 16 Myths of a Diabetic Diet, and has written for  publications including Diabetes Self-Management, Diabetes Spectrum, Clinical Diabetes, the Diabetes Research & Wellness Foundation’s newsletter,, and

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